diff --git a/src/org/jetbrains/jet/j2k/Converter.kt b/src/org/jetbrains/jet/j2k/Converter.kt
index 3139bf4e731..6cc5e9a9828 100644
--- a/src/org/jetbrains/jet/j2k/Converter.kt
+++ b/src/org/jetbrains/jet/j2k/Converter.kt
@@ -770,7 +770,7 @@ public fun createMainFunction(file: PsiFile): String {
 
     if (classNamesWithMains.size() > 0) {
         var className: String? = classNamesWithMains.get(0)?.getFirst()
-        return MessageFormat.format("fun main(args : Array<String?>?) = {0}.main(args)", className)!!
+        return MessageFormat.format("fun main(args : Array<String>) = {0}.main(args as Array<String?>?)", className)!!
     }
 
     return ""
diff --git a/tests/testData/ast/issues/file/kt-638.kt b/tests/testData/ast/issues/file/kt-638.kt
index 2bdbed1b2d5..d5a6a0ad7e1 100644
--- a/tests/testData/ast/issues/file/kt-638.kt
+++ b/tests/testData/ast/issues/file/kt-638.kt
@@ -35,4 +35,4 @@ var i3 : Identifier<Any?>? = Identifier.init<String?>("name")
 }
 }
 }
-fun main(args : Array<String?>?) = User.main(args)
\ No newline at end of file
+fun main(args : Array<String>) = User.main(args as Array<String?>?)
\ No newline at end of file
diff --git a/tests/testData/ast/issues/file/kt-871.kt b/tests/testData/ast/issues/file/kt-871.kt
index 69d9bdeef56..6f613625456 100644
--- a/tests/testData/ast/issues/file/kt-871.kt
+++ b/tests/testData/ast/issues/file/kt-871.kt
@@ -6,4 +6,4 @@ System.out?.println("Halo!")
 }
 }
 }
-fun main(args : Array<String?>?) = Program.main(args)
\ No newline at end of file
+fun main(args : Array<String>) = Program.main(args as Array<String?>?)
\ No newline at end of file
diff --git a/tests/testData/ast/switch/file/comlicatedFallDown.kt b/tests/testData/ast/switch/file/comlicatedFallDown.kt
index 60f4dd0466e..ff998f92dc2 100644
--- a/tests/testData/ast/switch/file/comlicatedFallDown.kt
+++ b/tests/testData/ast/switch/file/comlicatedFallDown.kt
@@ -85,4 +85,4 @@ for (i in 1..12) test(i)
 }
 }
 }
-fun main(args : Array<String?>?) = SwitchDemo.main(args)
\ No newline at end of file
+fun main(args : Array<String>) = SwitchDemo.main(args as Array<String?>?)
\ No newline at end of file
diff --git a/tests/testData/ast/switch/file/fallDown.kt b/tests/testData/ast/switch/file/fallDown.kt
index e27df742d64..35bb7e7576d 100644
--- a/tests/testData/ast/switch/file/fallDown.kt
+++ b/tests/testData/ast/switch/file/fallDown.kt
@@ -16,4 +16,4 @@ System.out?.println(monthString)
 }
 }
 }
-fun main(args : Array<String?>?) = SwitchDemo.main(args)
\ No newline at end of file
+fun main(args : Array<String>) = SwitchDemo.main(args as Array<String?>?)
\ No newline at end of file
diff --git a/tests/testData/ast/switch/file/kt-539.kt b/tests/testData/ast/switch/file/kt-539.kt
index aa9105769d8..4413070760e 100644
--- a/tests/testData/ast/switch/file/kt-539.kt
+++ b/tests/testData/ast/switch/file/kt-539.kt
@@ -49,4 +49,4 @@ System.out?.println(monthString)
 }
 }
 }
-fun main(args : Array<String?>?) = SwitchDemo.main(args)
\ No newline at end of file
+fun main(args : Array<String>) = SwitchDemo.main(args as Array<String?>?)
\ No newline at end of file